wildlifepediafandomcom-20200214-history
Black Bear
A small primitive bear called Ursus abstrusus is the oldest known North American fossil member of the genus Ursus, dated to 4.95 mya.[11] This suggests that U. abstrusus may be the direct ancestor of the American black bear, which evolved in North America.[9][12] Although Wolverton and Lyman still consider U. vitabilis an "apparent precursor to modern black bears",[13] it has also placed within U. americanus.[12] The ancestors of American black bears and Asiatic black bears diverged from sun bears 4.58 mya. The American black bear then split from the Asian black bear 4.08 mya.[9][14] The earliest American black bear fossils, which were located in Port Kennedy, Pennsylvania, greatly resemble the Asiatic species,[15] though later specimens grew to sizes comparable to grizzlies.[16] From the Holocene to present, American black bears seem to have shrunk in size,[9] but this has been disputed because of problems with dating these fossil specimens.[17] The American black bear lived during the same period as short-faced bears (Arctodus simus and A. pristinus) and the Florida spectacled bear (Tremarctos floridanus). These Tremarctine bears evolved from bears that had emigrated from Asia to North America 7–8 ma.[18] The short-faced bears are thought to have been heavily carnivorous and the FL spectacled bear more herbivorous,[19] while the American black bears remained arboreal omnivores, like their Asian ancestors. The black bear's generalist behavior allowed it to exploit a wider variety of foods and has been given as a reason why of these 3 genera, it alone survived climate and vegetative changes through and last ice age while the other more specialized North American predators went extinct. However, both Arctodus and Tremarctos had survived several other ice ages. After these prehistoric Ursids went extinct during the last glacial period 10,000 years ago, black bears were probably the only bear present in much of North America until the arrival of Brown bears to the rest of the continent.[16] http://en.wikipedia.org/w/index.php?title=American_black_bear&action=edit&section=3 edit SubspeciesEdit Listed alphabetically.[20] http://en.wikipedia.org/w/index.php?title=American_black_bear&action=edit&section=4 edit HybridsEdit American black bears are reproductively compatible with several other bear species, and have occasionally produced hybrid offspring. According to Jack Hanna's Monkeys on the Interstate, a bear captured in Sanford, Florida, was thought to have been the offspring of an escaped female Asian black bear and an American black bear.[26] In 1859, a black bear and a Eurasian brown bear were bred together in the London Zoological Gardens, but the three cubs did not reach maturity. In The Variation of Animals and Plants under Domestication Charles Darwin noted: In the nine-year Report it is stated that the bears had been seen in the Zoological Gardens to couple freely, but previously to 1848 most had rarely conceived. In the Reports published since this date three species have produced young (hybrids in one case),...[27]A huge black bear was shot in Autumn 1986 in Michigan, which was thought by some to be a black bear/grizzly bear hybrid, due to its unusually large size and its proportionately larger braincase and skull. DNA testing was unable to determine whether it was a black bear or grizzly.[28] http://en.wikipedia.org/w/index.php?title=American_black_bear&action=edit&section=5 edit Physical descriptionEdit [4][5]American black bears can be distinguished from brown bears by their smaller size, their more concave profiles, their shorter claws and the lack of a shoulder hump http://en.wikipedia.org/w/index.php?title=American_black_bear&action=edit&section=6 edit Build [6][7]Some specimens may develop a white “crescent moon” mark on the chest. This white mark, which is constant in Asiatic black bears, occurs in only 25% of American black bears[29]The skulls of American black bears are broad, with narrow muzzles and large jaw hinges. Females tend to have more slender and pointed faces than males. Their claws are typically black or grayish brown. The claws are short and rounded, being thick at the base and tapering to a point. Claws from both hind and front legs are almost identical in length, though the foreclaws tend to be more sharply curved. The hind legs are longer than those of Asiatic black bears. The tail is usually 4.8 inches (12 cm) long. The ears are small and rounded, and are set well back on the head. The soles of the feet are black or brownish, and are naked, leathery and deeply wrinkled. Black bears are highly dexterous, being capable of opening screw-top jars and manipulating door latches. They also have great physical strength, having been known to turn over flat-shaped rocks weighing 310 to 325 pounds (140 to 147 kg) by flipping them over with a single foreleg.[30] They move in a rhythmic, surefooted way and can run at speeds of 25–30 mph (40–50 km/h).[31] Black bears have good eyesight, and have been proven experimentally to be able to learn visual discrimination tasks based on color faster than chimpanzees and as fast as dogs. They are also capable of rapidly learning to distinguish different shapes, such as small triangles, circles and squares.[32] http://en.wikipedia.org/w/index.php?title=American_black_bear&action=edit&section=7 edit SizeEdit [8][9]Cinnamon-colored black bear in Yellowstone National ParkBlack bear weight tends to vary according to age, sex, health, and season. Seasonal variation in weight is very pronounced: in autumn, their pre-den weight tends to be 30% higher than in spring, when black bears emerge from their dens. Black bears on the East Coast tend to be heavier on average than those on the West Coast. Adult males typically weigh between 57–250 kg (130–550 lb), while females weigh 33% less at 41–109 kg (90–240 lb).[33] Adults have a typical size range of 120–200 cm (47–79 in) in length, and 70–105 cm (28–41 in) in shoulder height. The tail is 7.7–17.7 cm (3.0–7.0 in) long.[30][34][35][36] Although they are the smallest species in North America, large males exceed the size of other bear species except the Brown and Polar Bears.[30] The biggest wild American black bear ever recorded was a male from New Brunswick, shot in November 1972, that weighed 409 kg (900 lb) after it had been dressed, meaning it weigh an estimated 500 kg (1,100 lb) in life, and measured 2.4 m (7.9 ft) long.[37] The North American Bear Center, located in Ely, Minnesota, is home to the world's largest captive male and female black bears. Ted, the male, weighed 950–1,000 lb (430–450 kg) in the fall of 2006.[38] Honey, the female, weighed 555.5 lb (252.0 kg) in the fall of 2007.[39] http://en.wikipedia.org/w/index.php?title=American_black_bear&action=edit&section=8 edit PelageEdit [10][11]A white-furred Kermode black bearThe fur is soft, with dense underfur and long, coarse, thick guard hairs.[30] The fur is not as shaggy or coarse as that of brown bears.[37] American black bear skins can be distinguished from those of Asiatic black bears by the lack of a white mark on the chin and hairier footpads.[40] Despite their name, black bears show a great deal of color variation. Individual coat colors can range from white, blond, cinnamon, or light brown to dark chocolate brown or to jet black, with many intermediate variations existing. Bluish tinged black bears occur along a portion of coastal Alaska and British Columbia. White to cream colored black bears occur in coastal islands and the adjacent mainland of south-western British Columbia. Albino specimens have also been recorded.[41] Black coats tend to predominate in moist areas such as New England, New York, Tennessee, Michigan and western Washington. 70% of all black bears are black, though only 50% of black bears in the Rocky Mountains are black.[30] In his book The Great Bear Almanac, Gary Brown summarized the predominance of black or brown/blond specimens by location:[30] http://en.wikipedia.org/w/index.php?title=American_black_bear&action=edit&section=9 edit BehaviorEdit In his Great Bear Almanac, Gary Brown lists 20 different sounds in eight different contexts. Sounds expressing aggression include growls, woofs, snorts, bellows and roars. Sounds expressing contentment include mumbles, squeaks and pants. American black bears tend to be territorial and non-gregarious in nature. They mark their territories by rubbing their bodies against trees and clawing at the bark. Black bears are excellent and strong swimmers, doing so for pleasure and to feed. Black bears climb regularly to feed, escape enemies or to hibernate. Their arboreal abilities tend to decline with age.[31] Adult black bears are mostly nocturnal, but juveniles are often active in daytime.[12][13]Newborn black bear cubs http://en.wikipedia.org/w/index.php?title=American_black_bear&action=edit&section=10 edit Reproduction and development Sows usually produce their first litter at the age of 3–5 years.[31] Sows living in urban areas tend to get pregnant at younger ages.[42] The breeding period usually occurs in the June–July period, though it can extend to August in the species' northern range. The breeding period lasts for 2–3 weeks. Sows tend to be short tempered with their mates after copulating. The gestation period lasts 235 days, and litters are usually born in late January to early February. Litters usually consist of two cubs, though litters of 6 have been recorded. At birth, cubs weigh 10–16 ounces (280–450 g), and measure 8 inches in length. They are born with fine, gray, downlike hair, and their hind quarters are underdeveloped. They typically open their eyes after 28–40 days, and begin walking after 5 weeks. Cubs are dependent on their mother's milk for 30 weeks, and will reach independence at 16–18 months. At the age of six weeks, they attain 2 lb, by 8 weeks they reach 5 lb and by the age of 6 months they weigh 40–60 lb. They reach sexual maturity at the age of three years, and attain their full growth at 5 years.[31] The average lifespan in the wild is 18 years. The record age of a wild specimen was 31 years, while that in captivity was 44 years.[30] http://en.wikipedia.org/w/index.php?title=American_black_bear&action=edit&section=11 edit HibernationEdit [14][15]Mother black bear and cubs, hibernatingBlack bears were once not considered true or "deep" hibernators, but because of discoveries about the metabolic changes that allow black bears to remain dormant for months without eating, drinking, urinating, or defecating, most biologists have redefined mammalian hibernation as "specialized, seasonal reduction in metabolism concurrent with scarce food and cold weather". Black bears are now considered highly efficient hibernators.[43][44] Black bears enter their dens in October and November. Prior to that time, they can put on up to 30 pounds of body fat to get them through the seven months during which they fast. Hibernation in black bears typically lasts 3–5 months.[21] During this time, their heart rate drops from 40–50 beats per minute to 8 beats per minute. They spend their time in hollowed-out dens in tree cavities, under logs or rocks, in banks, caves, or culverts, and in shallow depressions. Females, however, have been shown to be pickier in their choice of dens, in comparison to males.[45] A special hormone, leptin is released into their systems, to suppress appetite. Because they do not urinate or defecate during dormancy, the nitrogen waste from the bear's body is biochemically recycled back into their proteins. This also serves the purpose of preventing muscle loss, as the process uses the waste products to build muscle during the long periods of inactivity. In comparison to true hibernators, their body temperature does not drop significantly (staying around 35 degrees Celsius) and they remain somewhat alert and active. If the winter is mild enough, they may wake up and forage for food. Females also give birth in February and nurture their cubs until the snow melts.[46] During winter, black bears consume 25–40% of their body weight.[47] The footpads peel off while they sleep, making room for new tissue. After emerging from their winter dens in spring, they wander their territories for two weeks so that their metabolism accustoms itself to the activity. They will seek carrion from winter-killed animals and new shoots of many plant species, especially wetland plants.[47] In mountainous areas, they seek southerly slopes at lower elevations for forage and move to northerly and easterly slopes at higher elevations as summer progresses. Black bears use dense cover for hiding and thermal protection, as well as for bedding. http://en.wikipedia.org/w/index.php?title=American_black_bear&action=edit&section=12 edit Dietary habitsEdit [16][17]Black bear feeding on a bush[18][19]Black bear taking a dead Salmon near Hyder, AlaskaUp to 85% of the black bear's diet consists of vegetation,[31] though they tend to dig less than brown bears, eating far fewer roots, bulbs, corms and tubers than the latter species.[41] Young shoots from trees and shrubs during the spring period are important to black bears emerging from hibernation, as they assist in rebuilding muscle and strengthening the skeleton and are often the only digestible foods available at that time. Berries, fruits, grasses, nuts and buds are often eaten.[48] During this period, they may also raid the nut caches of squirrels.[47] Black bears are fond of honey, and will gnaw through trees if hives are too deeply set into the trunks for them to reach them with their paws. Once the hive is breached, black bears will scrape the honeycombs together with their paws and eat them, regardless of stings from the bees.[37] The majority of the black bear's animal diet consists of insects such as bees, yellow-jackets, ants and their larvae.[47] Black bears will fish for salmon during the night, as their black fur is easily spotted by salmon in the daytime. However, the white furred black bears of the islands of western Canada have a 30% greater success rate in catching salmon than their black furred counterparts.[49] They will also prey on mule and white-tailed deer fawns in certain areas.[50][51][52] In addition they have been recorded preying on elk calves in Idaho[53] and moose calves in Alaska.[54] Black bear predation on adult deer is rare but has been recorded.[55][56][57] They may hunt adult moose by ambushing them as they pass by.[58] Black bears often drag their prey to cover, preferring to feed in seclusion and frequently begin feeding on the udder of lactating females, but generally prefer meat from the viscera. The skin of large prey is stripped back and turned inside out with the skeleton usually left largely intact. Unlike wolves and coyotes, black bears rarely scatter the remains of their kills. Vegetation around the carcass is usually matted down by black bears and their droppings are frequently found nearby. Black bears may attempt to cover remains of larger carcasses, though they do not do so with the same frequency as cougars and grizzly bears.[59] They may climb up to bald eagle nests to eat the eggs or chicks.[31] Black bears have been reported stealing deer and other animals from human hunters. http://en.wikipedia.org/w/index.php?title=American_black_bear&action=edit&section=13 edit Interspecific predatory relationshipsEdit Black bears tend to escape competition from brown bears by being more active in the daytime, and living in more densely forested areas. Violent interactions resulting in the deaths of black bears have been recorded in Yellowstone National Park.[60][61] Black bears may compete with cougars over carcasses. Like brown bears, they will sometimes steal kills from cougars. One study found that both bear species visited 24% of cougar kills in Yellowstone and Glacier National Parks, usurping 10% of carcasses.[62] Fights between the two species are rare, though they can be violent. Cremony, in his Life among the Apaches, describes an incident in which a cougar killed a black bear.[63] Black bear interactions with wolves are much rarer than with brown bears, due to differences in habitat preferences. The majority of black bear encounters with wolves occur in the species' northern range, with no interactions being recorded in Mexico. Despite the black bear being more powerful on a one to one basis, packs of wolves have been recorded to kill black bears on numerous occasions without eating them. Unlike brown bears, black bears frequently lose against wolves in disputes over kills.[64] Wolf packs are known to kill black bears during their hibernation cycle.[33] There is at least one record of a black bear killing a wolverine in a dispute over food in Yellowstone National Park.[65] http://en.wikipedia.org/w/index.php?title=American_black_bear&action=edit&section=14 edit Current range and populationEdit [20][21]Black bear at Grand Teton National ParkHistorically, black bears occupied the majority of North America's forested regions. Today, they are primarily limited to sparsely settled, forested areas.[66] Black bears currently inhabit much of their original Canadian range, though they do not occur in the southern farmlands of Alberta, Saskatchewan, and Manitoba. They have been extinct in Prince Edward Island since 1937. The total Canadian black bear population is between 396,000 and 476,000,[67] based on surveys taken in the mid 1990s in seven Canadian provinces, though this estimate excludes black bear populations in New Brunswick, Northwest Territories, Nova Scotia, and Saskatchewan. All provinces indicated stable populations of black bears over the last decade.[66] The current range of black bears in the United States is constant throughout most of the northeast (down to Virginia and West Virginia), the northern midwest, the Rocky mountain region, the west coast and Alaska. However it becomes increasingly fragmented or absent in other regions. Despite this, black bears in those areas seems to have expanded their range during the last decade. Surveys taken from 35 states in the early 1990s indicate that black bears are either stable or increasing, excepting Idaho and New Mexico. The overall population of black bears in the United States has been estimated to range between 339,000 and 465,000,[68] though this excludes populations from Alaska, Idaho, South Dakota, Texas, and Wyoming, whose population sizes are unknown.[66] As of 1993, known Mexican black bear populations existed in four areas, though knowledge on the distributions of populations outside those areas have not been updated since 1959. Mexico is the only country where the black bear is classed as endangered.[66] http://en.wikipedia.org/w/index.php?title=American_black_bear&action=edit&section=15 edit Relationships with humansEdit http://en.wikipedia.org/w/index.php?title=American_black_bear&action=edit&section=16 edit In folklore, mythology and cultureEdit [22][23]Harry Colebourn and Winnie, the bear from which Winnie the Pooh derives his nameBlack bears feature prominently in the stories of some of America's indigenous peoples. One tale tells of how the black bear was a creation of the Great Spirit, while the grizzly was created by the Evil Spirit.[69] In the mythology of the Haida, Tlingit, Tsimshian people of the Northwest Coast, mankind first learned to respect bears when a girl married the son of black bear Chieftain.[70] In Kwakiutl mythology, black and brown bears became enemies when Grizzly Bear Woman killed Black Bear Woman for being lazy. Black Bear Woman's children, in turn, killed Grizzly Bear Woman's own cubs.[71] The Navajo believed that the Big Black Bear was chief among the bears of the four directions surrounding Sun's house, and would pray to it in order to be granted its protection during raids.[72] Morris Michtom, the creator of the teddy bear, was inspired to make the toy when he came across a cartoon of Theodore Roosevelt refusing to shoot a black bear cub trapped up a tree.[73]Winnie the Pooh was named after Winnipeg, a female black bear cub that lived at London Zoo from 1915 until her death in 1934.[74] A black bear cub who in the spring of 1950 was caught in the Capitan Gap fire was made into the living representative of Smokey Bear, the mascot of the United States Forest Service.[75] http://en.wikipedia.org/w/index.php?title=American_black_bear&action=edit&section=17 edit Attacks on humansEdit See also: Bear attack and Bear dangerUnlike grizzly bears, which became a subject of fearsome legend among the European settlers of North America, black bears were rarely considered overly dangerous, even though they lived in areas where the pioneers had settled. Black bears rarely attack when confronted by humans, and usually limit themselves to making mock charges, emitting blowing noises and swatting the ground with their forepaws. However, according to Stephen Herrero in his Bear Attacks: Their Causes and Avoidance, 23 people were killed by black bears from 1900 to 1980. The number of black bear attacks on humans is higher than those of the brown bear, though this is largely because the black species outnumbers the brown rather than them being more aggressive.[24][25]The incidence of bear attacks in parks and campgrounds declined after the introduction of bear-resistant garbage cans and other reformsCompared to brown bear attacks, violent encounters with black bears rarely lead to serious injury. However, the majority of black bear attacks tend to be motivated by hunger rather than territoriality, and thus victims have a higher probability of surviving by fighting back rather than submitting. Unlike grizzlies, female black bears do not display the same level of protectiveness to their cubs, and seldom attack humans in their vicinity.[41] The worst recorded fatality incident occurred in May 1978, in which a black bear killed three teenagers who were fishing in Algonquin Park in Canada.[76] The majority of attacks happened in national parks, usually near campgrounds, where the bears had become habituated to human contact and food.[41] 1,028 incidences of black bears acting aggressively toward people, 107 of which resulted in injury, were recorded from 1964 to 1976 in the Great Smoky Mountains National Park, and occurred mainly in tourist hotspots where people regularly fed the bears handouts.[76] http://en.wikipedia.org/w/index.php?title=American_black_bear&action=edit&section=18 edit Livestock and crop predationEdit Livestock depredations by black bears occur mostly in spring. A limitation of food sources in early spring and wild berry and nut crop failures during summer months are probably major contributing factors. Black bears can do extensive damage in some areas of the northwestern United States by stripping the bark from trees and feeding on the cambium. Though black bears will attack adult cattle and horses, they seem to prefer sheep, goats, calves, and pigs. They normally kill by biting the neck and shoulders, though they may break the neck or back of prey with blows from the paws. Evidence of a bear attack includes claw marks and is frequently found on the neck, back, and shoulders of larger animals. Surplus killing of sheep and goats are common. Bears have been known to frighten livestock herds over cliffs, causing injuries and death to many animals; whether or not this is intentional is not known.[59] http://en.wikipedia.org/w/index.php?title=American_black_bear&action=edit&section=19 edit Hunting and exploitationEdit http://en.wikipedia.org/w/index.php?title=American_black_bear&action=edit&section=20 edit HuntingEdit Historically, black bears were hunted by both Native Americans and European settlers. Some Native American tribes, in admiration for the black bear's intelligence, would decorate the heads of bears they killed with trinkets, and place them on blankets. Tobacco smoke would be wafted into the disembodied head's nostrils by the hunter that dealt the killing blow, and would compliment the animal for its courage.[37] The Kutchin typically hunted black bears during their hibernation cycle. Unlike the hunting of hibernating grizzlies, which was wrought with danger, black bears took longer to awaken, and was thus safer and easier.[5] During the European colonisation of eastern North America, thousands of black bears were hunted for their meat, fat and fur.[10]Theodore Roosevelt wrote extensively on black bear hunting in his Hunting the Grisly and other sketches, in which he stated "in black bear chase there is much excitement, and occasionally a slight spice of danger, just enough to render it attractive; so it has always been eagerly followed". He wrote that black bears were difficult to hunt by stalking, due to their habitat preferences, though were easy to trap. Roosevelt described how in the Southern States, planters regularly hunted black bears on horseback with hounds. General Wade Hampton was known to have been present at 500 successful black bear hunts, two thirds of which he killed personally. He killed thirty or forty black bears with only a knife, which he would use to stab the bears between the shoulder blades while they were distracted by his hounds.[58] Unless well trained, horses were often useless in black bear hunts, as they often bolted when the bears stood their ground.[37] In 1799, 192,000 black bear skins were exported from Quebec. In 1822, 3,000 skins were exported from the Hudson's Bay Company.[77] In 1992, untanned, fleshed and salted black bear hides were sold for an average of $165.[78] In Canada, black bears are considered as both a big game and furbearer species in all provinces save for New Brunswick and Northwest Territories, where they are only classed as a big game species. There are currently 80,822 licensed black bear hunters in all of Canada. Canadian black bear hunts take place in autumn and winter, and both male and female bears can be legally taken, though some provinces prohibit the hunting of females with cubs, or yearling specimens.[66] Currently, 28 of the USA's states have black bear hunting seasons. Nineteen states require a bear hunting license, with some also requiring a big game license. In eight states, only a big game license is required to hunt black bears. Overall over 481,500 black bear hunting licences are sold per year. The hunting methods and seasons vary greatly according to state, with some bear hunting seasons including fall only, spring and fall, or year-round. New Jersey, in November 2010, approved of a six-day bear-hunting season in early December 2010 to slow the growth of the black bear population. Bear-hunting had been banned in New Jersey for five years.[79] A Fairleigh Dickinson University PublicMind poll found that 53% of New Jersey voters approved of the new season if scientists concluded black bears were leaving their usual habitats and destroying private property.[80] Men, older voters, and those living in rural areas were more likely to approve of a bear-hunting season in New Jersey than women, younger voters, and those living in more developed parts of the state.[80] In the western states, where there are large black populations, there are spring and year-round seasons. Approximately 18,845 black bears were harvested annually in the USA between 1988–1992. Within this period, annual harvests ranged from six bears in South Carolina to 2,232 in Maine.[66] According to Dwight Schuh in his Bowhunter's Encyclopedia, black bears are the third most popular quarry of bowhunters, behind deer and elk.[81] http://en.wikipedia.org/w/index.php?title=American_black_bear&action=edit&section=21 edit Meat and organsEdit Black bear meat had historically been held in high esteem among North America's indigenous people and colonists.[37] Black bears were the only bear species the Kutchin hunted for their meat, though this constituted only a small part of their diet.[5] According to the second volume of Frank Forester's field sports of the United States, and British provinces, of North America: The flesh of the black bear is savoury, but rather luscious, and tastes not unlike pork. It was once so common an article of food in New-York as to have given the name of Bear Market to one of the principal markets of the city. —''Frank Forester's field sports of the United States, and British provinces, of North America'' p. 186 Theodore Roosevelt himself likened the flesh of young black bears to that of pork, and not as coarse or flavourless as the meat of grizzlies.[82] The most favoured cuts of the black bear's meat are concentrated in the legs and loins. Meat from the neck, front legs and shoulders is usually ground into mincemeat or used for stews and casseroles. Keeping the fat tends to give the meat a strong flavour. As black bears can have trichinellosis, cooking temperatures need to be high in order to kill the parasites.[83] Black bear fat was once valued as a cosmetic article which promoted hair growth and gloss. The fat most favoured for this purpose was the hard white fat found in the body's interior. As only a small portion of this fat could be harvested for this purpose, the oil was often mixed with large quantities of hog lard.[37] However animal rights activism over the last decade has slowed the harvest of these animals; therefore the lard from black bear has not been used in recent years for the purpose of cosmetics.